Many different methods for the preparation of epoxides have been developed. Generally, epoxides are formed by the reaction of an olefin with an oxidizing agent in the presence of a catalyst. The production of propylene oxide from propylene and an organic hydroperoxide oxidizing agent, such as ethyl benzene hydroperoxide or tert-butyl hydroperoxide, is commercially practiced technology, see, e.g., U.S. Pat. Nos. 3,351,635 and 4,367,342. Another commercially practiced technology is the direct epoxidation of ethylene to ethylene oxide by reaction with oxygen over a silver catalyst. Unfortunately, the silver catalyst has not proved useful in commercial epoxidation of higher olefins.
Besides oxygen and organic hydroperoxides, another oxidizing agent useful for the preparation of epoxides is hydrogen peroxide. U.S. Pat. No. 4,833,260, for example, discloses the epoxidation of olefins with hydrogen peroxide in the presence of a titanium zeolite catalyst. Much current research is conducted in the direct epoxidation of olefins with oxygen and hydrogen. Many different direct epoxidation catalysts have been proposed. Typically, the catalyst comprises a noble metal that is supported on a titanium zeolite. For example, JP 4-352771 discloses the formation of propylene oxide from propylene, oxygen, and hydrogen using a catalyst containing a Group VIII metal such as palladium on a titanium silicalite.
One new titanium zeolite catalyst for use in olefin epoxidation reactions is titanium-MWW zeolite. Titanium-MWW zeolites are typically produced by a hydrothermal crystallization procedure, for example, as described in U.S. Pat. No. 6,759,540 and Wu et al., J. Phys. Chem. B, 2001, 105, p. 2897. Unfortunately, the previous processes to produce titanium-MWW are lengthy. The references teach high temperature crystallization processes, requiring prolonged heating at 130° C. for 1 day, 150° C. for 1 more day, and finally 170° C. for 5 or more days to complete the titanium-MWW synthesis.
In sum, new processes for producing titanium-MWW zeolites are needed. Particularly valuable would be processes that form high activity catalysts more efficiently.